Voici ma requête
et franchement, c'est peut-etre la fatigue, mais je vois pas mon SELECT
l.description,
(
SELECT a1.first_name||' '||a1.last_name
FROM agents a1
WHERE a1.birth_date =
(SELECT MAX(a.birth_date) FROM agents a WHERE a.location_id = l.location_id )
),

(
SELECT a2.first_name||' '||a2.last_name
FROM agents a2
WHERE a2.birth_date =
(SELECT MIN(a.birth_date) FROM agents a WHERE a.location_id = l.location_id)
FROM
locations l
;